I am attempting to create and access a Volume Shadow Copy snapshot using the Windows Power Shell in Windows 7. I found that I can create snapshots using the following via a previous superuser question:
(Get-WmiObject -list win32_shadowcopy).create("C:\","ClientAccessible")
I am unable to find any documentation indicating that it is possible to set a shadow copy to "Exposed" so that it can be mapped to a drive letter using WMI
. An article linked in the same question shows a hack using a junction to access the snapshot.
When I try to access the symlink, I get the following:
PS C:\Windows\system32> ls C:\shadowcopy
Get-ChildItem : The parameter is incorrect.
At line:1 char:3
+ ls <<<< C:\shadowcopy
+ CategoryInfo : ReadError: (C:\shadowcopy:String) [Get-ChildItem], IOException
+ FullyQualifiedErrorId : DirIOError,Microsoft.PowerShell.Commands.GetChildItemCommand
Attempting to access the snapshot directly gives the following:
PS C:\Windows\system32> ls '\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy14'
Get-ChildItem : Paths that begin with \\?\GlobalRoot are internal to the kernel and should not be opened by managed applications.
At line:1 char:3
+ ls <<<< '\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy14'
+ CategoryInfo : NotSpecified: (:) [Get-ChildItem], ArgumentException
+ FullyQualifiedErrorId : System.ArgumentException,Microsoft.PowerShell.Commands.GetChildItemCommand
How can I access a VSS snapshot from a powershell script?
How did you create the symlink? As outlined in that article, you have to specify the device path with a trailing backslash:
$s1 = (Get-WmiObject -List Win32_ShadowCopy).Create("C:\\", "ClientAccessible")
$s2 = Get-WmiObject Win32_ShadowCopy | Where-Object { $_.ID -eq $s1.ShadowID }
$d = $s2.DeviceObject + "\\"
Then $d
is your volume letter specifier:
cmd /c mklink /d C:\shadowcopy "$d"
After this, I was able to access the shadow copy mounted to C:\shadowcopy
just fine.
To unmount the shadow copy call $s2.Delete()
, as @KeyszerS pointed out in the comments.